urn or ATP were without effect in reversthe effects of diethylstilbesterol, dimes-.,1 or hexosterol on mitochondrial swelling.relatively large quantities o f inhil)itors needed to produce significant changes in mitochondria1 volume together with a lack of correlation of the relative abilities of thew (ASt ropenic suhs t ances to pr( ) t l~i ce sw11 i ng ;I 11 (1 potentiate 6-aiiiinonicot iii;imiclc tosicity on the 75.5 tiiii-rorf apparentlj-tliscount possil)lc iir viw cliaiiges in iiiitochoiitlri~il volirme. IKOc l u c w l by these compouiitls. as 1)eiiig pertin:~nt t o the I)iological results. 'l'htis, sul)seclutwt increases in niitochoi-rdrial i~ermealdity t o 6am i non icc t i ii am i t 1 e n ucl e( t i ( 1 e analogues containing (,-am iiion icot iiia 111 ic I(> may be ruled out as a niaj:)r factor iii vii-hai1c.i ng 6 -m i inon icoti ii;iiii itle :in t i i y i isni ( 1 i i I 1 t ra iii i t oc hc n t 1 r i ii 1 CJ 1 1 ZJ. iii es ( 1 e 1 )i' i! ( 1 (J t i t ( ) 11 Iritliiie nuc.leotitle. or pj-r id i n e ._ . + I )ic~th\~l..;till~c'..;lc.l.c:l :tiid Iic'sc!3ttw)l ;tw f a r 111::1'(t.iit.ctii.c th:tn c'.str;itlic-l, clicnc~..;tc*rctl ;iiicl ;)hIi,rriiii it1 pi t c'n t ia t ing t lit* :i ii I it 11 ni o I' ; i c t i ,.i 1 y 1 ) i I hc t i i:i c. i t I :1n t :icon ist G -:i in in on iwt iii;t iii ic It* iii t lit, 7.i . i t i i t11c ! 1' grin\n in 7.<5 1)lnck micc ( unlnil)li~Iic'tl cl;ita. 1)iclrich.

No abstract

Ingestion of cruciferous vegetables may prevent chemically induced carcinogenesis by their influence on specific cytochrome P450 enzymes (CYP) and phase II drug metabolizing enzymes in humans and rodents. Thus CYP enzymes are involved in transformation of procarcinogens, mutagens, steroid hormones and a large variety of other endogenous and exogenous components. In order to learn more about the influence of cruciferous vegetables on drug metabolizing enzymes in man two CYP enzymes previously suggested to be induced by vegetables were selected in an in vivo experiment in humans. Sixteen healthy non-smoking subjects, two females and 14 males, were exposed to three different types of diets and afterwards assayed for CYP1A2 catalysed caffeine metabolites and for CYP2E1 catalysed 6-hydroxylation of chlorzoxazone. Further, 2-hydroxyoestrone:16 alpha-hydroxylation ratios were determined in urine by means of a monoclonal antibody-based enzyme immunoassay. The three dietary periods were: (A) a customary home diet; (B) a 6 day standard diet avoiding well-known dietary inducers and inhibitors of CYP; (C) a 12 day dietary supplement to the standard diet of 500 g/day broccoli. The average 6-hydroxychlorzoxazone:chlorzoxazone ratio decreased by 21% (P < 0.05) after diet B compared with diet A in a 2 h plasma sample after ingestion of 500 mg chlorzoxazone. The ratio increased by 19% after diet C, however, this was not statistically significant. The caffeine metabolic ratio (CMR) was determined in urine 6 h after ingestion of 100 mg caffeine. The mean CMR increased by 5.5% when changing from diet A to diet B. When shifting to diet C the mean CMR increased a further 19% (P < 0.0005). The average 2-hydroxyoestrone:16 alpha-hydroxyoestrone ratio decreased by 1.3% when comparing diet A with diet B. Daily broccoli intake increased the ratio by 29.5% (P < 0.05). A low correlation of CMR with the 2-hydroxyoestrone:16 alpha-hydroxyoestrone ratio indicates that human CYP1A2 and other CYP enzymes involved in oestrone 2-hydroxylation are induced by dietary broccoli. On the other hand, the catalytic activity of CYP2E1 is not affected to the same degree by dietary broccoli.

No abstract

1. A lactate dehydrogenase isoenzyme present in human spermatozoa and semen was isolated and characterized biochemically in term of its pH for optimum activity and by means of K(m) values for lactate, NAD(+) and NAD analogues. The results were compared with those obtained with the human heart-type and the liver-type lactate dehydrogenase isoenzymes. 2. The enzyme was characterized by its resistance to digestion with different proteolytic enzymes. The time for 50% digestion in terms of residual dehydrogenase activity was compared with times obtained for the H(4)- and M(4)-types.